Liquid dispenser



United States Patent 3,333,549 LIQUID DISPENSER Rex C. Cooprider, Hacienda Heights, Calif., assignor to Calmar, Inc., City of Industry, Calif, a corporation of California Filed June 23, 1965, Ser. No. 466,262 20 Claims. (Cl. 103-158) ABSTRACT OF THE DISCLOSURE A liquid dispensing pump in which a tubular plunger closed at its upper end is disposed for reception in a housing. Extending into the housing through its lower end and held against reciprocation is a dip tube, the upper end of which is telescopically received in the plunger to define a pump chamber within the plunger. Such chamber communicates with the atmosphere through intercommunicating passages in the plunger and in the housing.

This invention relates to improvements in liquid dispensing pumps, and while not limited thereto, finds special utility in such pumps which dispense liquid in the form of a fine spray.

It has been customary for some time to sell various liquids such as cosmetics, deodorizers, medicines and the like, in containers equipped with pumps adapted for actuation by intermittent finger pressure and equipped with spray heads through which liquid is discharged in the form of a fine spray. Since the pumps are often discarded with their containers, it is important that they be capable of economical formation as well as eflicient operation.

With this in mind, the present invention contemplates the provision of a pump utilizing but three major components, each capable of production by conventional plastic molding operations, together with minor components consisting only of a conventional valve element and a pump spring. In accordance with the invention, the three said major components are adapted for simple and rapid assembly in a manner permitting them to be retained in fully assembled operative condition simply by fitting together of certain of the components without the necessity for other more conventional and more difficult operations such as cementing, welding, spinning or utilizing threaded or other fastening elements.

It is an object of the invention among others to provide such a pump structure in which two of the aforementioned major components cooperate with each other to define a sleeve valve operating in coordinated relation with the plunger stroke to control the discharge of liquid by the pump.

More particularly, it is an object to provide in a pump such a sleeve valve arrangement in which opening of the valve is delayed during the initial portion of the operative plunger stroke while the energy transmitted to the plunger is stored in an air cushion or other resiliently expansible and cont-ractible element within the pump chamber so that the ultimate opening of the sleeve valve permits immediate initiation of the discharge at a substantial pressure and at a substantial velocity. Where such an arrangement is employed in conjunction with a conventional spray head, it enables the formation of a spray pattern which is considerably more efiicient than would be the case if the sleeve valve were opened at the inception of the operative stroke, when the pressure is insufiicient to produce an efiicient spray pattern.

Still further important objects of the invention are to provide a pump structure in which the several cooperating parts may be readily assembled in operative condition without necessity for relative orientation about the pump axis and in which, when the pump plunger is spring projected to its outward inoperative position, means are provided automatically responsive to such projection for sealing the sleeve valve structure against leakage or seepage.

It is a still further object to provide a novel breather passage construction in such a pump in which the said sleeve valve automatically places the pump discharge orifice in communication with the contents of the container being dispensed incident to inception of the operative pump stroke, and automatically is held closed at the termination of each stroke to prevent leakage in the event of tilting or inversion of the container.

In the accompanying drawings, there is shown only the preferred embodiment of the invention together with certain modified details thereof, such disclosure being merely by way of exemplification of the invention and with the realization that it is capable of assuming numerous other forms and of variations as to its different details.

In the accompanying drawings:

FIGURE 1 is an axial section through a spray-type pump constructed in accordance with the invention, With a portion of the dip tube of the pump being broken away, the pump being shown in this view with the plunger in its fully raised or projected position prior to the inception of an operative pump stroke.

FIGURE 2 is a sectional view similar to FIGURE 1 but showing the pump with the plunger thereof in substantially its fully depressed position at substantially the end of an operative pump stroke.

FIGURE 3 is a detailed view partly in elevation and partly in section on the line 33 in FIGURE 1, showing the preferred arrangement of the spray orifice and its associated liquid discharge passages, the upper end of the dip tube or stationary piston being omitted from this view for the sake of clarity.

Referring now in detail to the accompanying drawings, and first considering generally the structure of the dispensing pump shown in FIGURES l and 2, it will be apparent that the pump comprises but three major parts, namely the generally tubular housing or casing A which is adapted for fixed connection to a liquid container and in which are supported the movable pump plunger B and the stationary pump piston C comprising the upper end of a dip tube or other liquid discharge conduit. In addition to these major components, the pump structure comprises only such conventional minor components as the ball check valve 10 and the plunger spring 11.

Considering the tubular housing or casing A in somewhat more detail, the same is preferably molded from a material such as polyethylene plastic of a resiliently flexible and stretchable nature. Its upper portion 12 comprises a combined valve sleeve and guide for cooperation with the plunger B and to this end is of uniform internal cross sectional shape, preferably being cylindrical. At its upper end, this valve portion or sleeve 12 of the housing is preferably formed with a radially inwardly and reversely directed re-entrant portion 13 of annular configuration having its lower periphery proportioned for snug sliding engagement with the hollow cylindrical plunger stem or extension 14 which projects upwardly therethrough and is closed at its upper end by fingerpiece 15 adapted to receive intermittent downward finger pressure for imparting reciprocation to the plunger B.

Formed integrally with the casing A is a spray head generally designated 16 which is defined by an orifice 17 opening through the cylindrical side wall of the plunger guide and valve sleeve 12 into its hollow interior, and

substantially concentrically surrounded by the usual generally cylindrical rim 18.

The plunger guide and sleeve valve portion 12 of the casing A opens downwardly into a sleeve-like cylindrical extension 20 which is adapted for reception in the mouth of a container, in the manner of a stopper. To better adapt the device for application to a conventional bottle or container there may be provided a generally conventional closure cap having an annular top wall 21 secured around the casing A in suitable manner, either as by forming it integrally therewith as illustrated or, if desired, by separately forming and snap-fitting or otherwise interconnecting the parts in accordance with conventional practice in the art here involved. The cap structure further includes a cylindrical skirt 22 depending from the top wall 21 concentrically and in spaced relation to the downward extension 20 of the casing. A snap rib 23 may be formed within the cap skirt for cooperation with a radially projecting rib or protuberance on the container neck in accordance with usual practice.

It will be seen that the plunger B is of generally inverted cup-like hollow configuration in which the cylindrical plunger body 24 is received in snug sliding engagement with the inner wall of the sleeve 12, its upwardly projecting closed end portion or stem 14 being of relatively reduced diameter for passage through the annular seal 13.

At its downwardly directed lower end, the plunger carries an annular outwardly projecting valve flange 25 adapted for flush sealing engagement with the downwardly directed shoulder or valve seat 26 provided at the juncture of the differing diameter inner bores of the sleeve portion 12 and extension 20 of the casing A.

Extending upwardly through the housing extension 20 and telescopically received in the downwardly opening plunger, in fluid-tight peripheral engagement with the iner face thereof, is a tubular piston 27 constituting the upper end of the dip tube 28. In the instant embodiment, the dip tube is adapted 'to extend into the liquid within the container preferably to a location adjacent the container bottom to withdraw liquid therefrom incident to the pumping action. Preferably the upper end portion of the piston 27 flares outwardly to a maximum diameter where it slidably engages the inner wall of the cylindrical plunger in snug substantially fluid-tight manner, as at 29. Above the maximum diameter portion 29 the upper extremity 30 of the piston is preferably inwardly tapered or flared to function as a pilot when the piston is initially inserted into the plunger during assembly. Further, to facilitate such insertion, the lower end of the cylinder itself is conically downwardly and outwardly flared as at 31.

Internally, the stationary piston 27 is formed with an upwardly presented valve seat 32 for cooperation with the ball valve to permit only a unidirectional upward flow of liquid from the container into the variable volume pump chamber 33 jointly defined by the plunger cylinder 24 and the piston 27.

The piston 27 is supported against axial displacement in the casing A preferably by means of a radially inwardly directed snap ring 34 at the lower end of the casing extension 20 having an upwardly diverging generally conical inner edge through which a radial supporting flange 35 on the dip tube 28 may be forced during assembly of the parts to thereafter rest on the abutting upper surface of the snap ring 34 and to be urged thereagainst by the plunger spring 11. The spring 11 is housed within the spring chamber defined around the piston 27 by the relatively radially spaced concentric casing extension 20 and the spring 11 is compressed between the flange 35 of the piston structure and the flange 25 at the lower end of the plunger 24.

The arrangemefit of the ball valve 10 and its cooperating seat 32 is generally conventional and such that as the pump chamber 33 is expanded by upward movement of the plunger cylinder 24, the ball will be lifted off of its seat 32 to permit upward flow of liquid through the dip tube 28 from the container and into the pump chamber.

For discharging the liquid from the pump chamber, the plunger 24 is provided with a liquid discharge port 36 which is positioned substantially below the closed upper end 15 ofthe plunger so that an air cushion may be trapped and retained above the valve port 36 for use in expelling the liquid contents of the pump chamber 33.

The plunger B and the housing A are respectively formed with separate sections of a discharge passage extending from the pump chamber to the atmosphere by way of the spray orifice 17 and including the said orifice 17 and port 36.

The passageway sections which serve to place the port 36 and orifice 17 in communication with each other may assume varying forms within the scope of the invention. In the preferred embodiment of the invention, the port 36 is normally closed by the overlying inner face of the sleeve 12 when the plunger is in its raised position, and the disposition of the said interconnecting passages or passage sections is such as to delay opening of the port 36 until approximately the end of the downward plunger stroke, so that the air entrapped within the upper end portion 14 of the plunger will be compressed to store energy which is suddenly released when communication is established at or near the end of the strokebetween the port 36 and orifice 17.

Thus the spray orifice 17 communicates with a circular depression 37 defining a swirl chamber on the inner face of the housing concentric to the inner endof orifice 17. An annular groove 38 also formed within the inner face of the housing and encircling the plunger is spaced axially above the swirl chamber 37 in position to register with the valve port 36 only near the fully depressed position of the plunger.

As is shown in FIGURE 3, one or more swirl passages such as 40 and 41 extend from the annular groove 38 and open tangentially into the swirl chamber 37 to impart a rapid swirling motion to the liquid sothat-the liquid as it passes through and emerges from the spray orifice 17 will be subjected to centrifugal force tending to cause it to break up into a fine spray pattern as it emerges from the orifice.

By withholding the discharge of spray until near the end of each operative plunger stroke, adequate, pressure is insured for causing the liquid to move through the swirl passages 40, 41, swirl chamber 37 and orifice 17 with suflicient velocity at the very inception of each stroke to cause it to thus emerge from the orifice 17 in a finely divided spray pattern and without the initial discharge from the orifice 17 of comparatively large drop.- lets of liquid. Such droplets, if formed, normally fall out of the spray pattern and are wasted. This frequently occurs where the discharge of spray is initiated immediately upon inception .of the downward plunger stroke, due to insuflicien-t pressure on the liquid at this time.

Obviously the position and axial extent of the groove 38 may be varied as desired in order to result in varying degrees of delay in opening of the port 36 on the .downward plunger stroke. While the groove or passageway 38 need not be annular as shown to thus completely encircle the plunger, this arrangement is highly desirable as eliminating any need for position of the parts to secure angular orientation between the port 36 and groove 38. It will further be apparent that the groove 38 may be formed in the plunger in communication with the port 36 rather seepage of the container contents through such passage during shipping of the filled containers to which the pumps of the invention are aflixed.

For this purpose, the lower end portion of the plunger body 24, commencing just above the flange 25, is made of slightly reduced diameter with respect to the surrounding valve sleeve 12 to define between the plunger B and casing A and annular breather passage 42. Normally in the raised condition of the plunger under the action of spring 11, the plunger flange 25 is maintained in sealing engagement with the stop shoulder 26 within the casing A to prevent communication between said passage and the container interior. However, immediately upon initiation of the downward rplunger stroke and throughout the major portion thereof, the unseating of the flange 25 from its cooperating shoulder or seat 26 will cause the breather passage 42 and orifice 17 to communicate with the spring chamber defined between the relatively spaced piston 27 and casing extension 20. The said spring chamber is at all times in communication with the container interior, as for instance through a breather opening 43 in the flange or ledge 35. The axial extent of the passage 42 is such that it is out of communication with the swirl chamber 37 and orifice 17 in the fully depressed position of the plunger depicted in FIGURE 2, being sealed off from these by the overlying inner wall of plunger 24.

In the operation of the liquid dispensing pump above described, the plunger spring 11 will normally maintain the plunger B in its fully upwardly projected position in which the plunger flange 25 is seated against the downwardly directed stop shoulder 26, both to limit the upward movement of the plunger and also to seal off the discharge orifice 17 and breather passage 42 from communication with the container interior. Thus in the event the container is wholly or partially inverted, the seated flange 25 by its sealingengagement with the shoulder 26 will prevent the liquid from escaping upwardly between casing A and plunger B to the discharge orifice 17. Also at this time, escape of liquid from the pump chamber 33 through the port 36, and thence upwardly through the upper end of the casing A will be prevented due to the fact that the port 36 will be closed by the surrounding casing. In addition, egress of liquid through the upper end of the casing will be prevented by the operative engagement of the annular seal 13 with the upwardly projecting plunger stem 14.

In order to operate the pump, finger pressure is intermittently applied to the closed upper end or fingerpiece 15 of the plunger stem to depress the plunger and to secure intermittent discharge of spray to the desired extent. Immediately upon initiation of the downward or operative plunger stroke, the ball valve is urged against its seat 32, and the flange 25 is unseated from the shoulder or seat 26 to place the interior of the container in communication with the atmosphere through the vent opening 34, breather passage 42, and orifice 17. Thus there is achieved substantial equalization between the air pressures on the interior and exterior of the container, while avoiding the formation of an air lock such as might impede the plunger operation.

Throughout substantially the entire downward movement of the plunger, the port 36 remains closed by the overlying inner fiace of the casing A so that air trapped within the upper portion 14 of the plunger above the orifice 17 will be increasingly compressed until the port 36 registers with the annular groove 38, at which time the port 36 will normally have descended to a level below that of the liquid in the pump chamber 33, assuming the latter to have been primed in obvious manner. As soon as such registry occurs, the stored energy within the compressed air is released. The ensuing sudden expansion of the compressed air will cause a sudden ejection of the liquid at substantially high pressure and velocity through the port 36, groove 38, swirl passages 40 and 41, and swirl chamber 37 for discharge through the orifice 17. It will be readily apparent, therefore, that the liquid will be caused immediately to enter the swirl chamber and to be whirled around therein at high velocity to thus pass through the orifice 17 in a rapidly rotating stream subjected to substantial centrifugal force for causing it to assume an extremely efiicient spray pattern.

After the compressed air within the plunger has expelled liquid from the pump chamber 33 to the level of the port 36, any air still entrapped in the plunger above atmospheric pressure, will then flow rapidly through the discharge passage 36, 38, 40, 41, 37 and 17, carrying with it any liquid and thus evacuating the passage. Therefore, on the next down stroke of the plunger, all of the liquid ejected through orifice 17 will have had its speed sufficiently accelerated by the time it reaches the swirl chamber 37 that it will be efficiently acted upon to produce a proper spray pattern.

As soon as finger pressure is released from the plunger B at the end of the operative pump stroke, the plunger will be urged upwardly by its return spring 11. At the inception of the upward movement, the port 36 will be displaced from registry with the annular groove 38 and thereby closed. The resulting expansion of the chamber 33 will unseat the ball valve 10 and the air pressureon the surface of the liquid within the container will force it upwardly through the dip tube 28 past the ball valve 10 and into the pump chamber 33 until the plunger reaches its uppermost limit as determined by the seating of the flange 25 against the annular shoulder or seat 26.

The intermittent pressure on the plunger will of course be repeated to cause ejection of spray as many times as may be desired, and at the end of each such intermittent actuation, the plunger will be automatically returned by spring pressure to its fully raised position in which the pump is sealed against leakage in the manner earlier described.

It will be noted that the pump structure of the invention comprises an exceedingly small number of parts adapted for assembly with a minimum number of operations. For instance, in assembling the several parts, the plunger B will first be inserted into the casing A through the downwardly opening extension 20 thereof, the flange 26 being proportioned for forcing through and beyond the snap ring 34 to substantially the shoulder 26. With the casing and plunger inverted, the ball valve 10 is then dropped into the open end of casing extension 20 and it is preferably brought to rest by abutment with the free end of a positioning finger or detent 45. The spring 11 also is inserted into the open end of the extension 20 and past the snap ring 34 thereof and into abutment with the plunger flange 25, following which the piston end of the dip tube 28 is inserted downwardly through the open end 20 of the inverted casing A. Its pilot end or portion 30 will obviously guide it into the open end of the plunger B and, incident to continued movement, it will encompass the ball valve 10 supported on the end of element 45. The insertion movement of the piston will be continued until the flange 35 thereon is forced or camrned past the snap ring 34, which will thereafter function as a supporting ledge beneath the said flange. The flange will then abut against the spring 11 which, in turn, will urge it against the snap ring 34 while urging the plunger against shoulder 26, so that normally the dip tube and plunger both will remain stationary. The depending ball supporting stem or element 45 of the plunger, in addition to thus positioning the ball during assembly of the parts, will also function during each downward stroke of the plunger to urge the ball toward a seated position in the event it may have become stuck or otherwise delayed in its return to the seat 32.

In this application I have shown only the preferred embodiment of the invention. However, it is to be recognized that the invention is capable of other and different embodiments and that its several features are capable of individual modification, all within the scope of the invention.

Having thus described my invention, I claim:

1. A liquid dispensing pump, comprising a sleeve-like housing open at both ends, a tubular plunger guided for reciprocation in said housing through one open end thereof, a dip tube having one end extending into the housing through the other open end thereof and defining an inlet port for the pump, said tube being supported in the housing against movement in the direction of said plunger reciprocation, said tubular plunger telescopically receiving said one end of the dip tube in snug substantially fluid-tight relation for reciprocation relative to the dip tube, said plunger and said dip t-ube thus jointly defining a variable volume pump chamber, check valve means controlling said inlet port to prevent reverse fiow of liquid from the pump chamber through the dip tube, said plunger being formed with an outlet opening from the pump chamber and said housing being formed with a discharge orifice, said housing and said plunger being formed to define jointly sections of a discharge passage which interconnects the said outlet opening with said discharge orifice throughout a predetermined range of the plunger reciprocation.

2. The combination of claim 1, including spring means in said housing urging said plunger upwardly.

3. The combination of claim 2 in which said spring means is compressed between said plunger and said piston.

' 4. The combination of claim 3, including upwardly and downwardly presented shoulders respectively spaced apart along the length of said housing, an outwardly directed flange around said plunger for engaging said downwardly presented shoulder for limiting the upward stroke of the plunger, said spring means comprising a coil spring encircling the tube and compressed between said flange and said upwardly presented shoulder.

5. A liquid dispensing pump comprising a sleeve-like housing having open upper and lower ends, an inverted cup-like plunger guided for reciprocation in said housing, said plunger and said housing respectively having interengaging stop means for limiting the upward stroke of said plunger, a tube supported at a fixed level in said housing with its upper end telescopically received in said plunger, a check valve in said tube, the lower end of said tube extending downwardly through the open lower end of said housing, said tube defining both a piston for cooperation with said plunger to form a variable volume pump chamber, and also an inlet port for said pump chamber, and said plunger being formed above said inlet port with an outlet opening.

.6. The combination of claim 5, including spring means compressed between said plunger and said tube.

7. A liquid dispensing pump comprising a sleeve-like housing of resiliently expansible material having an open upper end and an upwardly and inwardly directed snap ring at its lower end, and a downwardly directed stop shoulder spaced above said ring, a tube extending upwardly into the housing through said snap ring and having a cooperating outwardly extending flange proportioned for snap-fitting through said snap ring and normally supported thereon, an inverted cup-like plunger guided for reciprocation through the open upper end of said housing, an outwardly directed stop flange encircling the lower end of said tube, a spring enicrcling said plunger and compressed between the plunger and the tube to urge said plunger and said tube resiliently toward opposite ends of the housing with their respective flanges abutting against said snap ring and said stop shoulder, and restraining said tube against reciprocation with said plunger, a check valve in said tube, the upper end of said tube being snugly, telescopically received in said plunger to therewith define a variable volume pump chamber, said plunger and said housing respectively being formed with intercommunicating sections of a discharge passage from the pump chamber to the atmosphere.

8. The combination defined in claim 7 in which said housing is formed with a discharge orifice, and said plunger is formed with an opening from the pump chamber, said housing and plunger jointlydefining at their interface portions of said sections of a fluid discharge passage said portions interconnecting said orifice and said opening.

9. The combination defined in claim 8 in which said housing and said plunger respectively define cooperating portions of a sleeve valve, said sleeve valve being actuated by reciprocation of the plunger to permit discharge of fluid from the pump chamber only after a given amount of plunger movement.

v 10. The combination of claim 9 in which said plunger" includes an air chamber above said opening for storing a portion of the energy of the pump stroke.

11. A liquid dispensing pump comprising a tubular housing open at both ends and formed with an outlet opening therefrom between its ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, means for causing such reciprocation, a tubular piston extending upwardly through the lower end of said housing and supported at a fixed level in said housing with its upper end telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber, spring means with said housing exerting a resilient upward pressure on said plunger, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamber to the atmosphere and 7 including said orifice, and said discharge passage section of the plunger including a valve port opening outwardly through said plunger at a location below its closed upper end, said discharge passage sections being positioned out of communication with each other in the fully raised position of the plunger and in communication 'with each other during a portion of each downward stroke of the plunger.

12. A liquid dispensing pump comprising a tubular housing open at both ends and formed with a discharge orifice opening therefrom between its .ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, said plunger projecting upwardly through the upper end of said housing for reception of actuating finger pressure, a tubular piston extending through the lower end of said housing and supported at a fixed level in said housing with its upper end telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber,

spring means with said housing exerting a resilient ,up-.

ward pressure on said plunger, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamher to the atmosphere and including said orifice, and said discharge passage section of the plunger including a valve port opening outwardly through said plunger at a location below its closed upper end, said respective discharge passage sections being axially spaced from each other in the raised position of the plunger and relatively positioned to communicate with each other only after completion of a predetermined portion of each downward plunger stroke. a

13. The combination defined in claim 12 in which said discharge passage includes a circular depression defining a swirl chamber on the inner face of said housing concentric to the inner end of said orifice, an annular groove in said inner face encircling said plunger and spaced axially above said swirling chamber in position to register with said valve port only near the fully depressed position of said plunger whereby to delay the discharge of liquid through said orifice until the end of each plunger stroke,

'9 and a swirl passage extending from said annular groove and opening tangentially into said swirl chamber.

14. The combination defined in claim 12 in which said discharge passage includes a circular depression defining a swirl chamber on the inner face of said housing concentric to the inner end of said orifice, an annular liquid conduit jointly defined between said plunger and housing encircling said plunger and spaced axially above said swirl chamber in position to register with said valve port only after partial depression of said plunger whereby to delay the discharge of liquid through said orifice until after partial completion of each plunger stroke, said housing being formed with a swirl passage extending from said annular liquid conduit and opening tangentially into said swirl chamber.

15. A liquid dispensing pump comprising a tubular housing open at both ends and formed with a discharge orifice opening therefrom between its ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, actuating means projecting from said plunger upwardly through the upper end of said housing for transmitting actuating finger pressure to said plunger, said housing including an annular inwardly projecting snap ring adjacent its lower end, a tubular piston extending upwardly through the lower end of said housing and restrained against movement in the direction of said plunger reciprocation, said piston being telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber, said piston having an outward projection thereon of larger diameter than said snap rib for force-fitting through the snap rib and for supporting the piston above said snap rib at a fixed level within said housing, a coil spring in said housing exerting a resilient upward pressure on said plunger, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamber to the atmosphere and including said orifice and a valve port through the wall of said plunger at a location normally above the upper end of said piston but below the closed upper end of said pump chamber to provide for a retention of a cushion of air in the upper portion of said pump chamber.

16. A liquid dispensing pump comprising a tubular housing open at both ends and formed with a discharge orifice opening therefrom between its ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, actuating means projecting from said plunger upwardly through the upper end of said housing for transmitting actuating finger pressure to said plunger, said housing presenting a downwardly directed internal annular shoulder, an annular outwardly projecting valve flange carried by said plunger beneath said shoulder for abutting sealing engagement with said shoulder, a tubular piston supported at a fixed level within said housing and telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber, a coil spring in said housing encircling said piston and exerting a resilient upward pressure on said plunger, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamber to the atmosphere and including said orifice and a valve port through the wall of said plunger, said plunger being of relatively reduced cross section from a location spaced below said valve port to coact with said housing in defining an annular breather space normally disconnected from said valve port and communicating with said orifice, said flange cooperating with said stop shoulder both to limit the upward stroke of the plunger and to function as a valve for controlling communication between said orifice and the lower portion of said housing.

17. A liquid dispensing pump comprising a tubular housing open at both ends and formed with a discharge orifice opening therefrom between its ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, actuating means projecting from said plunger upwardly through the upper end of said housing for transmitting actuating finger pressure to said plunger, said housing including a downward extension of larger internal cross section than the rest of said housing and presenting a downwardly directed internal annular shoulder at its juncture with said extension, and an annular inwardly projecting snap ring adjacent its lower end, an annular outwardly projecting valve flange carried by said plunger cylinder for abutting sealing engagement with said shoulder, a tubular piston extending upwardly through the lower end of said housing and telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber, said piston having an outward projection thereon of larger diameter than said snap rib for force fitting through the snap rib and for supporting the piston above said snap rib at a fixed level within said housing, said housing extension being spaced outwardly from the piston to define an annular spring chamber therearound, said spring chamber being vented through a breather opening in said piston flange, a coil spring in said spring chamber encircling said piston and exerting a resilient upward pressure on said plunger, said spring being compressed between said flanges on the plunger and piston respectively, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamber to the atmosphere and including said orifice and a valve port through the wall of said plunger at a location normally above the upper end of said piston but below the closed upper end of said pump chamber to provide for retention of a cushion of air in the upper portion of said pump chamber.

18. The combination of claim 17 in which said discharge passage includes a circular depression defining a swirl chamber on the inner face of said housing concentric to the inner end of said orifice, an annular groove in said inner face encircling said plunger and spaced axially above said swirl chamber in position to register with said valve port only near the fully depressed position of said plunger whereby to delay the discharge of liquid through said orifice until the end of each plunger stroke, and a swirl passage extending from said annular groove and opening tangentially into said swirl chamber.

19. The combination of claim 18 in which said plunger is of relatively reduced cross section from its said flange for a distance upwardly therefrom exceeding the axial spacing between said swirl chamber and said annular shoulder to coact with said housing in defining an annular breather space normally extending from said swirl chamber to the flange, said flange cooperating with said stop shoulder both to limit the upward stroke of the plunger and to function as a valve for controlling communication between said orifice and said vent opening.

20. A liquid dispensing pump comprising a tubular housing open at both ends and formed with a discharge orifice opening therefrom between its ends, a hollow downwardly opening inverted cup-like plunger disposed for axial reciprocation in said housing, actuating means projecting from said plunger upwardly through the upper end of said housing for transmitting actuating finger pressure to said plunger, said housing including a downward extension of larger internal cross section than the rest of said housing and presenting a downwardly directed internal annular shoulder at its juncture with said extension, and an annular inwardly projecting snap ring adjacent its lower end, an annular outwardly projecting valve flange carried by said plunger for abutting sealing engagement with said shoulder, a tubular piston supported at 11' a fixed level within said housing and telescopically received in the downwardly opening plunger to therewith define a variable volume pump chamber, check valve means in said tubular piston preventing back flow of liquid from the pump chamber, said housing extension being spaced outwardly from the piston to define an annular spring chamber therea-round, a coil spring in said spring chamber encircling said piston and exerting a resilient upward pressure on said plunger, said spring being compressed between said flanges on the plunger and piston respectively, said plunger and said housing respectively being formed with separate sections of a discharge passage extending from said pump chamber to the atmosphere andincluding said orifice and a valve port through the wall of said plunger at a. location normally above the upper end of said piston but below the closed upper end of said pump chamber to provide for retention of a cushion of air in the upper portion of said pump chamber, said plunger and housing being formed to provide a breather space extending from a location spaced below said valve port substantially to saidfiange, said flange cooperating with ,said stop shoulder both to limit the ,upward stroke of the plunger and to function as a valve for controlling communication between said orifice and said spring chamber.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A LIQUID DISPENSING PUMP, COMPRISING A SLEEVE-LIKE HOUSING OPEN AT BOTH ENDS, A TUBULAR PLUNGER GUIDED FOR RECIPROCATION IN SAID HOUSING THROUGH ONE OPEN END THEREOF, A DIP TUBE HAVING ONE END EXTENDING INTO THE HOUSING THROUGH THE OTHER OPEN END THEREOF AND DEFINING AN INLET PORT FOR THE PUMP, SAID TUBE BEING SUPPORTED IN THE HOUSING AGAINST MOVEMENT IN THE DIRECTION OF SAID PLUNGER RECIPROCATION, SAID TUBULAR PLUNGER TELESCOPICALLY RECEIVING SAID ONE END OF THE DIP TUBE IN SNUG SUBSTANTIALLY FLUID-TIGHT RELATION FOR RECIPROCATION RELATIVE TO THE DIP TUBE, SAID PLUNGER AND SAID DIP TUBE THUS JOINTLY DEFINING A VARIABLE VOLUME PUMP CHAMBER, CHECK VALVE MEANS CONTROLLING SAID INLET PORT TO PREVENT REVERSE FLOW OF LIQUID 